U.S. patent number 5,486,352 [Application Number 08/367,650] was granted by the patent office on 1996-01-23 for sunscreen compositions.
This patent grant is currently assigned to Elizabeth Arden Company. Invention is credited to Angel A. Guerrero.
United States Patent |
5,486,352 |
Guerrero |
January 23, 1996 |
**Please see images for:
( Certificate of Correction ) ** |
Sunscreen compositions
Abstract
A cosmetic sunscreen composition is described that includes an
emulsion formed from water, an emollient oil and an organic
sunscreen agent capable of absorbing ultraviolet radiation within
the range of 290 to 400 nm. Further included in the sunscreen
composition is a microfluidized medium formulated and
microfluidized separately and prior to blending with the other
aforementioned components. This medium includes water, a
phospholipid, and an organic sunscreen agent identical to that in
the emulsion. The combination of identical sunscreen agents in
different environments provides an overall increase in SPF for the
overall sunscreen composition.
Inventors: |
Guerrero; Angel A. (Huntington,
CT) |
Assignee: |
Elizabeth Arden Company (New
York, NY)
|
Family
ID: |
23448043 |
Appl.
No.: |
08/367,650 |
Filed: |
January 3, 1995 |
Current U.S.
Class: |
424/59; 424/60;
514/937; 514/938 |
Current CPC
Class: |
A61K
8/068 (20130101); A61K 8/37 (20130101); A61K
8/553 (20130101); A61Q 17/04 (20130101); Y10S
514/937 (20130101); Y10S 514/938 (20130101) |
Current International
Class: |
A61K 007/42 () |
Field of
Search: |
;424/59,60
;514/937,938 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chang; Ceila
Assistant Examiner: Huang; Evelyn
Attorney, Agent or Firm: Honig; Milton L.
Claims
What is claimed is:
1. A sunscreen composition comprising:
(i) from about 1 to about 90% by weight of water;
(ii) from about 1 to about 90% by weight of an emollient oil;
(iii) from about 0.1 to about 30% by weight of an organic sunscreen
agent with a chromophoric group active within the ultraviolet
radiation range from 290 to 400 nm; and
(iv) from about 0.1 to about 50% by weight of a microfluidized
medium comprising:
from about 1 to about 80% by weight of water;
from about 0.001 to about 5% by weight of a phospholipid;
from about 1 to about 50% by weight of an organic sunscreen agent
identical to that of component (iii), and the medium being
formulated and microfluidized prior to blending with components (i)
to (iii).
2. A composition according to claim 1 wherein the organic sunscreen
agent is selected from the group consisting of benzophenone-3,
benzophenone-4, benzophenone-6, benzophenone-8, benzophenone-12,
butyl methoxy dibenzoyl methane, PABA, octyl dimethyl PABA, octyl
methoxycinnamate and combinations thereof.
3. A composition according to claim 2 wherein the organic sunscreen
agent is octyl methoxycinnamate.
4. A composition according to claim 1 wherein the emollient oil
present in highest concentration is cyclomethicone, dimethicone
copolyol and mixtures thereof.
5. A composition according to claim 1 wherein the microfluidized
medium further comprises from about 1 to about 30% by weight of a
silicone oil.
6. A composition according to claim 5 wherein the silicone oil of
the microfluidized medium is selected from the group consisting of
cyclomethicone, dimethicone copolyol and mixtures thereof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to sunscreen compositions, particularly those
in lotion and cream form.
2. The Related Art
Sunscreen compositions are commonly used during outdoor work or
leisure for protection of exposed skin against sunburn, cancer and
even photo ageing. Many effective sunscreen preparations are sold
commercially or are described in cosmetic or pharmaceutical
literature. In general, sunscreen preparations are formulated as
creams, lotions or oils containing as the active agent an
ultraviolet radiation absorbing chemical compound. The active agent
functions by blocking passage of erythematogenic radiation thereby
preventing its penetration into the skin.
The ideal sunscreen formulation should be non-toxic and
non-irritating to skin tissue and be capable of convenient
application in a uniform continuous film. The product should be
sufficiently chemically and physically stable so as to provide an
acceptable shelf life upon storage. It is particularly desirable
that the preparation should retain its protective effect over a
prolonged period after application. Thus, the active agent when
present on the skin must be resistant to chemical or
photodegradation, to absorption through the skin, and to removal by
perspiration, skin oil, or water. For aesthetic reasons, the
product should be substantially odorless (or be capable of being
scented) and be non-staining to the skin or clothing.
Sunscreen agents in the order of decreasing effectiveness may be
categorized as either highly chromophoric monomeric organic
compounds, inorganic compounds and minimally chromophoric polymeric
organic solids.
U.S. Pat. No. 5,219,558 (Woodin, Jr. et al.) and U.S. Pat. No.
4,919,934 (Deckner et al.) disclose photoprotection compositions
wherein the active sunscreen agents are of the chromophoric
monomeric organic compound variety. The examples feature the
commercially common sunscreens such as octyl methoxycinnamate
(Parsol MCX), benzophenone-3 (Oxybenzone) and octyl dimethyl
PABA.
Chromophoric monomeric organic compounds are subject to certain
problems. One of the more important problems is that of skin
irritation. Some people are quite sensitive to organic molecules
with chromophoric groups. Adverse allergic reactions can result.
Incidentally, increasing the concentration of a sunscreen does not
necessarily increase the SPF, and indeed has shown may decrease the
protective factor. This negative response has been attributed by
some to micelle interference with the sunscreen over concentration.
Therefore, it would be quite desirable to minimize the level of
such compounds in any sunscreen compositions. Total replacement of
chromophoric organic compounds, while desirable, is presently not
feasible for high SPF compositions that also require certain types
of aesthetics.
Inorganic particulate compounds such as titanium dioxide have been
employed as sunscreen agents. In fact, titanium dioxide is quite
popular with marketers advertising them as "natural sunscreens".
The problem with inorganic particulate compounds is that high SPF
values can only be achieved with high concentrations of these
materials. Unfortunately, aesthetics suffer at such high
concentrations. Clear formulas become opaque. High loadings also
tend to form visible white films on the skin which consumers
perceive negatively.
Polymeric organic particulates are a final category of materials
which have found use in sunscreen formulations. U.S. Pat. No
5,008,100 (Zecchino et al.) reports oil-in-water emulsions
containing polyethylene particles as a co-active sunscreen agent
along with the traditional chromophoric organic compounds. Similar
to the inorganic materials, polymeric particles are limited in
their sunscreen effectiveness. High amounts of such materials will
have adverse effects upon the formula aesthetics.
Accordingly, it is an object of the present invention to provide a
sunscreen composition that maximizes the sun protection factor but
minimizes the level of chromophoric monomeric organic compound.
Another object of the present invention is to provide a sunscreen
composition in the form of an oil and water emulsion that exhibits
improved aesthetics when applied to the skin.
Yet another object of the present invention is to provide a
sunscreen composition having a much lower human irritancy than
formulas of equivalent sun protection factor.
These and other objects of the present invention will more readily
become apparent from the description and examples which follow.
SUMMARY OF THE INVENTION
A sunscreen composition is provided which includes:
(i) from about 1 to about 90% by weight of water;
(ii) from about 1 to about 90% by weight of an emollient oil;
(iii) from about 0.1 to about 30% by weight of an organic sunscreen
agent with a chromophoric group active within the ultraviolet
radiation range from 290 to 400 nm; and
(iv) from about 0.1 to about 50% by weight of a microfluidized
medium that includes:
from about 1 to about 80% by weight of water;
from about 0.001 to about 5% by weight of a phospholipid; and
from about 1 to about 50% by weight of an organic sunscreen agent
identical to that of component (iii), and the medium being
formulated and microfluidized prior to blending with components (i)
to (iii).
DETAILED DESCRIPTION OF THE INVENTION
Now it has been discovered that a microfluidized medium containing
an organic sunscreen agent when blended into an emulsion containing
further amounts of an identical organic sunscreen agent will
provide to resultant compositions a significant boost in the sun
protection factor (SPF). The organic sunscreen agent outside of the
microfluidized medium will ordinarily be soluble in the emollient
oil phase of the emulsion. Organic sunscreen agent trapped within
the microfluidized medium will ordinarily be delivered via the
medium to the water phase of the emulsion. As a consequence, the
oil and water emulsion has identical organic sunscreen agent
distributed both in the oil and the water phases. Much greater SPF
efficiency is thereby achieved.
Accordingly, sunscreen compositions of the present invention will
be emulsions containing an oil and a water phase. Water
constituting the latter phase will be present in an amount from
about 1 to about 90% by weight thereof. Preferably the level of
water will range from about 30 to about 80%, optimally between
about 50 and about 70% by weight.
Emollient materials will form the oil phase of emulsions according
to the present invention. These emollient materials may be in the
form of hydrocarbons, silicones, synthetic or natural esters and
combinations thereof. Amounts of the emollient oil will range from
about 1 to about 90%, preferably from about 10 to about 60%,
optimally from about 15 to about 25% by weight.
Hydrocarbons may be in the form of mineral oil, terpenes (such as
squalene), isoparaffins and petroleum jelly.
Silicone oils may be divided into the volatile and non-volatile
variety. The term "volatile" as used herein refers to those
materials which have a measurable vapor pressure at ambient
temperature. Volatile silicone oils are preferably chosen from
cyclic or linear polydimethylsiloxanes containing from about 3 to
about 9, preferably from about 4 to about 5, silicon atoms. Linear
volatile silicone materials generally have viscosities less than
about 5 centistokes at 25.degree. C. while cyclic materials
typically have viscosities of less than about 10 centistokes.
Examples of commercially available volatile silicone oils are Dow
Corning.RTM. 344 and Dow Corning.RTM. 345.
Nonvolatile silicone oils useful as an emollient material include
polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane
copolymers. The essentially non-volatile polyalkyl siloxanes useful
herein include, for example, polydimethyl siloxanes with
viscosities of from about 5 to about 100,000 centistokes at
25.degree. C. Among the preferred non-volatile emollients useful in
the present compositions are the polydimethyl siloxanes having
viscosities from about 10 to about 400 centistokes at 25.degree.
C.
Silicone copolyols are particularly useful as emollient and
emulsifying materials within the context of the present invention.
Particularly preferred is Dow Corning.RTM. 3225C fluid, a mixture
of cyclomethicone and dimethicone copolyol having viscosity at
25.degree. C. of 600-2000 cps and a specific gravity of about
0.963.
Among the ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon
atoms. Examples thereof include isoarachidyl neopentanoate,
isononyl isononanoate, oleyl myristate, oleyl stearate, octyl
stearate and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty
alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty
acid esters, diethylene glycol mono- and di-fatty acid esters,
polyethylene glycol (200-6000) mono- and di-fatty acid esters,
propylene glycol mono- and di-fatty acid esters, polypropylene
glycol 2000 monooleate, polypropylene glycol 2000 monostearate,
ethoxylated propylene glycol monostearate, glyceryl mono- and
di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated
glyceryl monostearate, 1,3-butylene glycol monostearate,
1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid
ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan
fatty acid esters are satisfactory polyhydric alcohol esters.
(4) Wax esters such as beeswax, spermaceti, myristyl myristate,
stearyl stearate.
(5) Mono-, Di- and Triglyceride esters such as PEG-8
caprylic/capric triglyceride.
(6) Sterols esters, of which cholesterol fatty acid esters are
examples thereof.
Blended within the aforementioned emulsions of the present system
will be an organic sunscreen agent having at least one chromophoric
group absorbing within the ultraviolet range somewhere from 290 to
400 nm. Chromophoric organic sunscreen agents may be divided into
the following categories (with specific examples) including:
p-Aminobenzoic acid, its salts and its derivatives (ethyl,
isobutyl, glyceryl esters; p-dimethylaminobenzoic acid);
Anthranilates (o-aminobenzoates; methyl, menthyl, phenyl, benzyl,
phenylethyl, linalyl, terpinyl, and cyclohexenyl esters);
Salicylates (octyl, amyl, phenyl, benzyl, menthyl, glyceryl, and
dipropyleneglycol esters); Cinnamic acid derivatives (menthyl and
benzyl esters, .alpha.phenyl cinnamonitrile; butyl cinnamoyl
pyruvate); Dihydroxycinnamic acid derivatives (umbelliferone,
methylumbelliferone, methylaceto-umbelliferone); Trihydroxycinnamic
acid derivatives (esculetin, methylesculetin, daphnetin, and the
glucosides, esculin and daphnin); Hydrocarbons (diphenylbutadiene,
stilbene); Dibenzalacetone and benzalacetophenone;
Naptholsulfonates (sodium salts of 2-naphthol-3,6-disulfonic and of
2-naphthol-6,8-disulfonic acids); Dihydroxy-naphthoic acid and its
salts; o- and p-Hydroxybiphenyldisulfonates; Coumarin derivatives
(7-hydroxy, 7-methyl, 3-phenyl); Diazoles
(2-acetyl-3-bromoindazole, phenyl benzoxazole, methyl
naphthoxazole, various aryl benzothiazoles); Quinine salts
(bisulfate, sulfate, chloride, oleate, and tannate); Quinoline
derivatives (8-hydroxyquinoline salts, 2-phenylquinoline);
Hydroxy-or methoxy-substituted benzophenones; Uric and vilouric
acids; Tannic acid and its derivatives (e.g., hexaethylether);
(Butyl carbityl) (6-propyl piperonyl) ether; Hydroquinone;
Benzophenones (Oxybenzone, Sulisobenzone, Dioxybenzone,
Benzoresorcinol, 2,2',4,4'-Tetrahydroxybenzophenone,
2,2'-Dihydroxy-4,4'-dimethoxybenzophenone, Octabenzone;
4-isopropyldibenzoylmethane; Butylmethoxydibenzoylmethane;
Etocrylene; and 4-isopropyl-dibenzoylmethane).
Particularly useful are: 2-ethylhexyl p-methoxycinnamate,
4,4'-t-butyl methoxydibenzoylmethane,
2-hydroxy-4-methoxybenzophenone, octyldimethyl p-aminobenzoic acid,
digalloyltrioleate, 2,2-dihydroxy-4-methoxybenzophenone, ethyl
4-[bis(hydroxypropyl)]aminobenzoate,
2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate,
glyceryl p-aminobenzoate, 3,3,5-trimethylcyclohexylsalicylate,
methylanthranilate, p-dimethylaminobenzoic acid or aminobenzoate,
2-ethylhexyl p-dimethylaminobenzoate,
2-phenylbenzimidazole-5-sulfonic acid,
2-(p-dimethylaminophenyl)-5-sulfoniobenzoxazoic acid and mixtures
thereof.
Suitable commercially available organic sunscreen agents are those
identified under the following table.
TABLE I
__________________________________________________________________________
CTFA NAME TRADE NAME SUPPLIER
__________________________________________________________________________
Benzophenone-3 UVINUL M-40 BASF Chemical Co. Benzophenone-4 UVINUL
MS-40 BASF Chemical Co. Benzophenone-8 SPECTRA-SORB UV-24 American
Cyanamid DEA-Methoxycinnamate BERNEL HYDRO Bernel Chemical Ethyl
dihydroxypropyl-PABA AMERSCREEN P Amerchol Corp. Glyceryl PABA NIPA
G.M.P.A. Nipa Labs. Homosalate KEMESTER HMS Humko Chemical Menthyl
anthranilate SUNAROME UVA Felton Worldwide Octocrylene UVINUL N-539
BASF Chemical Co. Octyl dimethyl PABA AMERSCOL Amerchol Corp. Octyl
methoxycinnamate PARSOL MCX Bernel Chemical Octyl salicylate
SUNAROME WMO Felton Worldwide PABA PABA National Starch
2-Phenylbenzimidazole-5-sulphonic acid EUSOLEX 6300 EM Industries
TEA salicylate SUNAROME W Felton Worldwide
2-(4-Methylbenzlidene)-camphor EUSOLEX 6300 EM Industries
Benzophenone-1 UVINUL 400 BASF Chemical Co. Benzophenone-2 UVINUL
D-50 BASF Chemical Co. Benzophenone-6 UVINUL D-49 BASF Chemical Co.
Benzophenone-12 UVINUL 408 BASF Chemical Co. 4-Isopropyl dibenzoyl
methane EUSOLEX 8020 EM Industries Butyl Methoxy dibenzoyl methane
PARSOL 1789 Givaudan Corp. Etocrylene UVINUL N-35 BASF Chemcial Co.
__________________________________________________________________________
Amounts of the aforementioned sunscreen agents will generally range
from about 0.1 to about 30%, preferably from about 2 to about 20%,
optimally from about 4 to about 10% by weight.
Optionally there may be present in the sunscreen emulsion
compositions of the present invention a variety of other materials.
Examples include fatty acids, humectants, thickeners/viscosifiers,
surfactants, preservatives, biologically active materials and other
adjunct ingredients. These are described more fully below.
Fatty acids having from 10 to 30 carbon atoms may also be included
in the compositions of this invention. Illustrative of this
category are pelargonic, lauric, myristic, palmitic, stearic,
isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic,
behenic and erucic acids.
Humectants of the polyhydric alcohol-type may also be included in
the compositions of this invention. The humectant aids in
increasing the effectiveness of the emollient, reduces scaling,
stimulates removal of built-up scale and improves skin feel.
Typical polyhydric alcohols include glycerol (known also as
glycerin), polyalkylene glycols and more preferably alkylene
polyols and their derivatives, including propylene glycol,
dipropylene glycol, polypropylene glycol, polyethylene glycol and
derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene
glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated
glycerol, propoxylated glycerol and mixtures thereof. For best
results the humectant is preferably propylene glycol. The amount of
humectant may range anywhere from 0.5 to 30%, preferably between 1
and 15% by weight of the composition.
Thickeners/viscosifiers in amounts from about 0.01 to about 5% by
weight of the composition may also be included. As known to those
skilled in the art, the precise amount of thickeners can vary
depending upon the consistency and thickness of the composition
which is desired. Exemplary thickeners are xanthan gum, sodium
carboxymethyl cellulose, hydroxyalkyl and alkyl celluloses
(particularly hydroxypropyl cellulose), and cross-linked acrylic
acid polymers such as those sold by B. F. Goodrich under the
Carbopol trademark.
Surfactants may also be present in cosmetic compositions of the
present invention. Total concentration of the surfactant will range
from about 0.1 to about 40%, preferably from about 1 to about 20%,
optimally from about 1 to about 5% by weight of the total
composition. The surfactant may be selected from the group
consisting of anionic, nonionic, cationic and amphoteric actives.
Particularly preferred nonionic surfactants are those with a
C.sub.10 -C.sub.20 fatty alcohol or acid hydrophobe condensed with
from about 2 to about 100 moles of ethylene oxide or propylene
oxide per mole of hydrophobe; the C.sub.2 -C.sub.10 alkyl phenols
condensed with from 2 to 20 moles of alkylene oxide; mono- and di-
fatty acid esters of ethylene glycol; fatty acid monoglyceride;
sorbitan, mono- and di- C.sub.8 -C.sub.20 fatty acids; and
polyoxyethylene sorbitan as well as combinations thereof. Alkyl
polyglycosides and saccharide fatty amides (e.g. methyl
gluconamides) are also suitable nonionic surfactants.
Preferred anionic surfactants include soap, alkyl ether sulfate and
sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates,
alkyl and dialkyl sulfosuccinates, C.sub.8 -C.sub.20 acyl
isethionates and combinations thereof.
Compositions of the present invention may also contain C.sub.1
-C.sub.20 .alpha.-hydroxycarboxylic acids and salts thereof. The
salts are preferably alkalimetal, ammonium and C.sub.1 -C.sub.12
alkanolammonium salts. Illustrative acids are glycolic acid, lactic
acid and 2-hydroxycaprylic acid. Most preferred is a combination of
glycolic and 2-hydroxycaprylic acids and their ammonium salts.
Levels of these materials may range from about 0.01 to about 15%,
preferably from about 0.1 to about 9%, optimally between about 0.5
and about 7% by weight of the cosmetic composition.
Preservatives can desirably be incorporated into the cosmetic
compositions of this invention to protect against the growth of
potentially harmful microorganisms. Suitable traditional
preservatives for compositions of this invention are alkyl esters
of para-hydroxybenzoic acid. Other preservatives which have more
recently come into use include hydantoin derivatives, propionate
salts, and a variety of quaternary ammonium compounds. Cosmetic
chemists are familiar with appropriate preservatives and routinely
choose them to satisfy the preservative challenge test and to
provide product stability. Particularly preferred preservatives are
disodium EDTA, phenoxyethanol, methyl paraben, propyl paraben,
imidazolidinyl urea (commercially available as Germall 115.RTM.),
sodium dehydroacetate and benzyl alcohol. The preservatives should
be selected having regard for the use of the composition and
possible incompatibilities between the preservatives and other
ingredients in the emulsion. Preservatives are preferably employed
in amounts ranging from about 0.01% to about 2% by weight of the
composition.
Minor adjunct ingredients may also be present in the cosmetic
compositions. These ingredients include vitamins (such as Vitamin
B.sub.6, Vitamin C, ascorbyl palmitate, Vitamin A palmitate,
Vitamin E acetate, biotin, niacin and DL-panthenol), amino acids
(such as glycine and serine), ceramides (such as Ceramide I and
Ceramide III), biohyaluronic acid (with oligosaccharides, available
as Actiglide J.RTM. from Active Organics US) and sodium PCA.
Natural vegetable materials from renewable resources are often
desirable in cosmetic compositions. For instance, cosmetic
compositions of the present invention may include p-glucan derived
from oats, commercially available under the trademark Microat SF
from Nurture Inc., Missoula, Mont. Another natural material is
plant pseudocollagen commercially available from Brooks, Inc.,
South Plainfield, N.J.
Amounts of each of the foregoing materials may range from about
0.001 to about 10%, preferably from about 0.05 to about 1%,
optimally between about 0.1 and 0.5% by weight.
Colorants, fragrances, opacifiers and abrasives may also be
included in compositions of the present invention. Each of these
substances may range from about 0.05 to about 5%, preferably
between 0.1 and 3% by weight.
Besides the water and emollient oil components, sunscreen emulsion
compositions of the present invention require the presence of a
microfluidized medium component. The medium will contain water, a
phospholipid, and an organic sunscreen agent identical to that
within the water and emollient oil emulsion. The medium is
formulated and microfluidized prior to blending with the water,
emollient oil and first portion of the organic sunscreen agent.
Amounts of water in the microfluidized medium may range from about
1 to about 80%, preferably from about 30 to about 75%, optimally
from about 65 to about 70% by weight of the medium. The amount of
phospholipid may range from about 0.01 to about 5%, preferably from
about 0.01 to about 2%, optimally from about 0.5 to about 1% by
weight of the medium. The amount of organic sunscreen agent within
the medium may range from about 1 to about 50%, preferably from
about 5 to about 35%, optimally from about 12 to about 24% by
weight of the medium.
A further material which can improve the stability of the
microfluidized medium will be a silicone oil. Particularly
effective will be a combination of dimethicone copolyol and
cyclomethicone, commercially available as Dow Corning.RTM. 3225C.
Amounts of the silicone oil may range from about 1 to about 30%,
preferably from about 5 to about 20%, optimally between about 8 and
15% by weight of the medium.
Sunscreen cosmetic compositions of the present invention may be in
any form. These forms may include creams, lotions, sticks, roll-on
formulations, mousses, aerosol sprays and pad-applied formulations.
Most preferred are creams and lotions.
As earlier noted, compositions of the present invention require a
portion of the organic sunscreen to be suspended in a
microfluidized medium. Microfluidization is a well-known processing
technique. Microfluidization can be described as the dynamic
interaction of two fluid streams in precisely defined microchannels
resulting in the production of fine emulsions and dispersions with
narrow size distribution. A fine emulsion is defined as one in
which the droplet size of the dispersed phase is substantially
below one micron, usually in the range of from 0.0001 to 0.8
micron, preferably from 0.01 to 0.5 micron.
The process may be conducted in an air-driven microfluidizer
operating at pressures up to 10,000 psi. Feedstock can be premixed
or the individual phases left separate and fed coaxially. Product
may be continuously processed or recycled via a closed loop.
Intensity of fluid stream interactions and the resultant emulsion
fineness is controllable by changes in interaction chamber
configuration, pressure and number of passes.
The following Examples will more fully illustrate the embodiments
of this invention. All parts, percentages and proportions referred
to herein and in the appended claims are by weight unless otherwise
indicated. These weight percentages relate to the total sunscreen
composition (i.e. emulsion plus microfluidized medium) except where
otherwise specified.
EXAMPLE 1
A series of experiments were conducted to evaluate the SPF
contribution from sunscreen agents both outside and within a
microfluidized medium. Table I sets forth the base composition of
the fully formulated product, except without sunscreen.
In-vitro SPF of the formulated product, was measured with an
SPF-290 Analyzer, manufactured by Optometrics USA, Inc. of Ayer,
Mass.
The optical system of the SPF-290 is comprised of a continuous
UV-VIS source, color compensating filters, diffusion plates, a
grating monochromator and detector. Ultra-violet (UVB) and near
ultra-violet (UVA) radiation is provided by a Xenon arc lamp. The
radiation emitted from the source is attenuated in such a way that
it more closely resembles the solar spectrum. The beam of radiation
reaches the sample and, at that point, is either transmitted,
absorbed or reflected by the sample or substrate. Transmitted
radiation passes through a series of diffuser plates which further
attenuate it. Then the beam enters a monochromator and, ultimately,
the monochromatic radiation impinges on the photosensitive surface
of the detector, generating a signal that is proportional to the
intensity of the radiation striking the surface.
The method of measurement involved applying 80 microliters of
sample onto a Vitro-Skin.RTM. substrate (commercially available
from Innovative Measurement Solutions, Inc.) supported by a holder.
The sample was applied to an area of 6.4.times.6.4 cm.sup.2 in such
a manner that a surface was covered approximating 40 cm.sup.2. An
amount of sample equal to 2 microliters per cm.sup.2, which is
similar to that used in standard in-vivo SPF tests, was distributed
on the test substrate. SPF measurements were then taken on the
sample formulas.
TABLE I ______________________________________ BASE COMPOSITION
COMPONENT WEIGHT % ______________________________________ Potassium
Lactate 10.0000 Silicone Fluid 344 6.1000 Octyl Methoxycinnamate
4.0000 Potassium Hydroxide (45% Soln.) 3.0000 C.sub.12 -C.sub.15
Alkyl Benzoate 2.9000 Dimethicone Copolyol 2.3000 Propylene Glycol
2.0000 Glycerin 2.0000 Octyl Stearate 1.2000 Octyl Dodecyl
Neopentanoate 1.1000 Cetyl Dimethicone 0.6500 Silicone Fluid 200
(10 cst) 0.4500 Polyglyceryl-2 Beeswax 0.4000 Dimethicone Copolyol
Beeswax 0.4000 Urea 0.2500 Squalene 0.2000 Polyglyceryl Ricinoleate
0.2000 Saccharide Isomerate 0.2000 Sodium PCA 0.2000 Propylparaben
0.1000 Methylparaben 0.1000 Disodium EDTA 0.1000 Ceramide 0.0011
Deionized Water to 100 ______________________________________
Under Table II there are reported the SPF of the base emulsion and
of variations of the base composition with Parsol MCX (octyl
methoxycinnamate).
TABLE II ______________________________________ SUNSCREEN
COMPONENTS A B C D E ______________________________________ Parsol
MCX (within Base 4 5.12 4.00 0 0 Emulsion but external of
Microfluidized Medium) Parsol MCX (within 0 0 1.12 1.12 0
Microfluidized Medium) None (Base Emulsion) 96 94.88 94.88 98.88
100 ______________________________________
TABLE III ______________________________________ SUNSCREEN ACTIVITY
A B C D E ______________________________________ SPF 14.7 13.1 17.1
6.3 1.1 ______________________________________
Formula A demonstrates that Parsol MCX.RTM. in the water and
emollient oil emulsion provides an SPF of 14.7 as compared to
Formula E without any sunscreen with an SPF of 1.1. A slight
increase of the sunscreen agent to 5.12% in Formula B provided an
SPF of 13.1. When the extra 1.12% Parsol MCX.RTM. carried within
the microfluidized medium was dosed to the base emulsion, the SPF
rose to 17.1. Formula D which includes only 1.12% Parsol MCX.RTM.
as delivered via the microfluidized medium displayed an
exceptionally high SPF of 6.3. From these results it is seen that
the combination of a sunscreen agent having a portion within the
base emulsion and a another portion within the microfluidized
medium can result in an overall composition of higher than expected
SPF value.
EXAMPLE 2
A series of cream sunscreen type compositions according to the
present invention are described below.
TABLE IV ______________________________________ WEIGHT % COMPONENTS
A B C D E F ______________________________________ Dow Corning 3225
.RTM. 14.00 14.00 14.00 20.00 18.00 18.00 Microfluidized Medium*
9.00 12.00 16.00 16.00 7.50 7.50 Aluminum Stearate Gel 4.00 4.00
4.00 4.00 4.00 4.00 4** Parsol MCX .RTM. 3.00 3.00 6.00 2.00 3.00
3.00 Sodium Chloride 3.00 3.00 3.00 3.00 3.00 3.00 Butylene Glycol
2.50 2.50 2.50 2.50 2.50 2.50 Actiglide J .RTM. 2.20 2.20 2.20 2.20
2.20 2.20 Glycerin 1.50 1.50 1.50 1.50 1.50 1.50 Sodium Lactate (in
water) 1.00 1.00 1.00 1.00 1.00 1.00 Urea 1.00 1.00 1.00 1.00 1.00
1.00 Squalene 1.28 1.28 1.28 1.28 1.28 1.28 Cetyl Dimethicone 1.00
1.00 1.00 1.00 1.00 1.00 Silicone Fluid 344 0.70 0.70 0.70 0.70
0.70 0.70 Cetyl Dimethicone 0.30 0.30 0.30 0.30 0.30 0.30 Copolyol
Chitosan Lactate 0.20 0.20 0.20 0.20 0.20 0.20 Tocopheryl Acetate
0.20 0.20 0.20 0.20 0.20 0.20 Glycine 0.50 0.50 0.50 0.50 0.50 0.50
Sodium PCA 0.50 0.50 0.50 0.50 0.50 0.50 Glydant Plus .RTM. 0.10
0.10 0.10 0.10 0.10 0.10 Disodium EDTA 0.10 0.10 0.10 0.10 0.10
0.10 Plant Pseudocollagen 0.10 0.10 0.10 0.10 0.10 0.10 Colorant
0.10 0.10 0.10 0.10 0.10 0.10 Ceramide I and III 0.07 0.07 0.07
0.07 0.07 0.07 Hydroxycaprylic Acid 0.05 0.05 0.05 0.05 0.05 0.05
Ascorbyl Palmitate 0.02 0.020 0.20 0.20 0.20 0.20 Beta Glucan 0.01
0.01 0.01 0.01 0.01 0.01 L-Serine 0.01 0.01 0.01 0.01 0.01 0.01
Water to to to to to to 100 100 100 100 100 100
______________________________________ *Contains 22.5% Parsol MCX
.RTM., 10% Dow Corning 3225C; Phenoxyethanol; Paraben; Phospholipid
and the balance water. **Cetyl Octanoate/Aluminum Distearate
EXAMPLE 3
A further set of experiments were conducted to evaluate the SPF
contribution from sunscreen agents both outside and within a
microfluidized medium. Table V sets forth the base composition of a
fully formulated product, except without sunscreen. Test protocol
was identical to that described under Example 1.
TABLE V ______________________________________ BASE COMPOSITION
COMPONENTS WEIGHT % ______________________________________ Dow
Corning 3225C .RTM. 14.00 Aluminum Stearate Gel 5.00 Glycerin 3.00
Sodium Chloride 3.00 Butylene Glycol 2.00 Squalene 1.28 Actiglide J
.RTM. 1.50 Cetyl Dimethicone 1.00 Urea 1.00 Sodium Lactate Solution
1.00 Glycine 0.50 Sodium PCA 0.50 Chitosan Lactate 0.20 Tocopheryl
Acetate 0.20 Cetyl Dimethicone Copolyol 0.20 Glydant Plus .RTM.
0.10 Disodium EDTA 0.10 Plant Pseudocollagen 0.10 0.5% FD&C Red
#4 0.08 Ceramide 0.07 Fragrance 0.05 Hydroxycaprylic Acid 0.05
Colorant 0.40 Ascorbyl Palmitate 0.02 Beta Glucan 0.01 L-Serine
0.01 Silicone Fluid 344 0-0.7 Deionized Water to 100
______________________________________
TABLE VI ______________________________________ SUNSCREEN
COMPONENTS A B C D E F ______________________________________
Parsol MCX (within 0 0 0 5.0 6.0 3.0 Base Emulsion but external of
Microfluidized Medium) Parsol MCX (within 0 2.0 4.0 0 0 2.0
Microfluidized Medium) None (Base Emulsion) 100 98.0 96.0 95.5 94.0
95.0 ______________________________________
TABLE VII ______________________________________ SUNSCREEN ACTIVITY
A B C D E F ______________________________________ SPF 1.0 7.3 8.7
12.7 15.8 16.9 ______________________________________
From Table VII it is evident that Parsol MCX.RTM. when distributed
between both the oil and water phases as in Formula F exhibited the
highest SPF. Formula D which had a higher amount of Parsol MCX.RTM.
(6%) than that of Formula F nevertheless exhibited a lower SPF than
the latter composition. From these results it is again seen that
the combination of sunscreen agent having a portion within the base
emulsion and another portion within the microfluidized medium can
result in an overall composition of higher than expected SPF
value.
The foregoing description and Examples illustrate selected
embodiments on the present invention. In light thereof, various
modifications will be suggested to one skilled in the art, all of
which are within the spirit and purview of this invention.
* * * * *